Magnetically coupled pump structure

ABSTRACT

Centrifugal pump apparatus of the magnetically-coupled type suitable for tank mounting and also including improvements in impeller and spindle structures of general application and for use with very hot liquids and corrosive chemicals. A cup-shaped motor mounting bell is provided for insertion, open side out, into a hole in the side of a tank and has a flange attaching to the tank wall. The motor is supported on mounting formations inside of the large well afforded by the bell. A smaller cupshaped magnet well is formed by recessing inwardly on the bottom of the cup-shaped bell, which is also provided with sealing land closing and sealing with the open side of the pump housing. The driven coupling magnet of the pump fits into the small magnet well which is surrounded by the larger motor-driven magnet in the larger well. The pump impeller and magnet rotate on spindle means supported at both ends and which may be integrally conformed at one end with a part of the pump structure.

United States Patent 1 1, 3,802,804 Zimmermann Apr. 9, 1974 MAGNETICALLY COUPLED PUMP Primary Eraminer-William L. Freeh [75] Inventor:

Deerfield, Ill. 1 1 ABSTRACT [73] Assignee: March Manufacturing Company, Centrifugal m apparatus of magnetically Skokie m coupled type suitable for tank mounting and also including improvements in impeller and spindle struc- Filed! y 21, 1967 tures of general application and for use with very hot [21] Appl No; 655,109 liquids and corrosive chemicals. A cup-shaped motor mounting bell is provided for insertion, open side out, into a hole in the side of a tank and has a flange at- [52] U.S. Cl. 417/360, 417/420 taching to the tank wall. The motor is Supported on [51] Int. Cl. F04b 35/04 mounting formations inside of the large we" ff d d [58] Field of Search 103/87, 87 M; 230/15 MC; by the bell A smaner cup shaped magnet we" is 310/104; 64/28 M; 192/ 84 PM; 417/420, 360 formed by recessing inwardly on the bottom of the I cup-shaped bell, which is also provided with sealing 156] References Clied land closing and sealing with the open side of the UNITED STATES PATENTS pump housing. The driven coupling magnet of the 2,970,548 2/1961 Berner.... 417/420 P p fits into the Small magnet Well which is 3,398,695 8/1968 P1111 103/87 M rounded y the g r m r-driven magnet in the 3,411,450 11/1968 Clifton 103/87 M larger well. The pump impeller and magnet rotate on R26,094 10/1966 Zimmermann 103/87 M pindle means supported at both ends and which may 2,855,141 10/1953 h j 230/117 A be integrally conformed at one end with a part of the 3,133,573 8/1964 Bergey et a1 310/104 pump Structure .819 1/1967 McCoy 103/87 M 3 Claims, 9 Drawing Figures "2 J /2,4 55 32 33 f a: 22 A 4 9 f2 4: 2/ 1, I. '3' I 54 204 111 i 65' {a 23 3 59 7 l l r l D I 27 1 "26 I C3 0 A I, L "-7 /0 2 51 i in I 7 fih 1 J I 205 5g, 52

/2,9 :7 if 1 ".Ju

STRUCTURE Frederick N. Zimmermann,

Attorney, Agent, or Firm Cal1ard Livingston 1 MAGNETICALLY COUPLED PUMP STRUCTURE This invention relates to improvements in magnetically-coupled pumps of the centrifugal type wherein an impeller is rotated in a sealed chamber by means of concentric ring magnets or the like, one of which is fixed on the impeller hub and the other of which is external to the sealed chamber and driven by motor means.

Because the impeller shaft need not penetrate the sealed chamber, such pumps are free of leakage of the displaced liquid and are commonly used in wholly submerged installations to circulate chemicals and very hot liquids for which purposes the impellers and pump bodies are frequently constructed of molded plastic materials.

The presently-disclosed improvements relate particularly to a type of construction in which the impeller rotates upon a spindle fixed in cantilever fashion at only one end oh a wall portion of a pump body which is made in two separable sections, one section constituting a closure for the other. Such a spindle may be integrally formed with the pump body whether the latter be made of metal or non-metallic plastic materials; but extreme working temperatures, particularly in the case of plastic materials, can cause the spindle to skew outof alignment and disable the pump whether the spindle is of the integral type or a separate metallic member fastened to a wall of the pump body.

In order to utilize the advantages of the type of construction described, including especially the internallysupported and isolated spindle means, the invention provides as one of its features that that one of the two body members of the pump housing assembly to which the spindle is not attached shall be provided with means for receiving and supporting the free or unattached end of the spindle when the two body members are fitted together, whereby the alignment of the spindle is fixed.

The present disclosures further utilize and afford improvements in the type of pump body and motor mounting structure described in a copending application Ser. No. 584,171, now abandoned, wherein one of two complementary body members, which in assembly comprise the pump housing, serves as a closure for an open side portion of the other body member and is formed with two axially-aligned but oppositely-opening and mutually sealed-off wells, one of which closes the open side of the other body member and contains the inner or driven coupling magnet, while the outer well contains the driving magnet and supports the motor externally, the present improvement residing in the formation of the outer well with a depth to receive part (or all) of the motor, and the further provision at the rim of this outer or motor-mounting well of a sealing and clamping flange affording a means for mounting the entire assembly in a hole in the side of a tank in which the pump will be submerged while the motor unit will be exposed for access exteriorly of the tank.

In the novel pump structure the pump impeller rotates on a stationary spindle primarily supported at one of its ends on a wall portion of the pump body, and the opposite end thereof removably engages a stabilizing support means, such as a socket or recess formed in a closure member for an opposite open side portion of the pump body to prevent skewing of the spindle, especially in the case of synthetic plastic constructions subject to softening or distortion from extreme temperav tures or chemical action in the circulated liquid. Further features are:

1. the closure member includes as part thereof oppositely-opening wells having common imperforate separating wall portions, the driven magnet of the impeller being fitted into one of the wells and the driving magnet and driving motor being contained and supported in the other well;

2. the spindle stabilizing support means for the opposite end of the spindle is a recess formed in the bottom of the appertaining one of the wells;

3. the closure member is in the form of a cylindrical bell housing with the two wells respectively opening into opposite axial ends thereof, and that one of the wells which contains the driving magnet and motor is provided with a mounting flange adapted for clamping and sealing the entire structure in a hole in the side of a tank with the motor unit exposed exteriorly of the tank and the pump submerged in the tank contents;

4. the spindle may be separable from or integral with that one of the pump body members providing the primary support, and has its opposite end removably fitting into an imperforate receptacle or socket formed in the other body member.

The several features above described and other aspects of novelty and utility are more particularly described in the following specification taken in view of the annexed drawings in which:

FIG. 1 is a vertical section through a temperature control tank employing the improved pump structure, parts being shown in elevation and diagrammatically;

FIG. 2 is a vertical sectional detail of the pump structure, parts being shown fragmentally and in elevation to enlarged scale;

' FIG. 3 is an elevational detail of the open side of the pump body drawn to reduced scale;

FIG. 4 is an elevational view of the outer face of the pumpmounting bell or housing;

FIG. 4 is a view into the bell from the outer side obverse to that of FIG. 4;

FIG. 6 is a cross-section of a pump body, similar to that of FIG. 2, showing a modified form of the closure and spindle support;

FIG. 7 is an enlarged perspective detail of the spindle of FIG. 6;

FIG. 8 is an elevational viewof the pump body of FIG. 6 at the open side thereof;

FIG. 9 is a sectional detail similar to FIG. 6 but showing a modified spindle structure.

The improved pump structure is illustrated in FIG. 1 in conjunction with temperature control apparatus wherein the pump 10 is wholly submerged in a temperature regulating bath 11 contained in a tank 12 for the purpose of circulating a tempering liquid from a source 13 via inlet and outlet ducts l4 and 15 through a heatexchanging means 16 in order to change the temperature of the bath through a considerable range of 158 or more, responsive to temperature sensing and control means (not shown) serving among other functions to control the pump motor 40.

As seen to larger scale in FIG. 2, the pump 10 is of a magnetically-coupled type which completely isolates the pumping chamber from an external driving means so that there can beno possible contamination of the tank contents by the circulated tempering liquid as a result of any leakage from the pump spindle.

Such a pump may be of the character disclosed in US. Pat. No. Re.26,094 with additional features disclosed in a copending application Ser. No. 584,17 l and will .comprise a pump body having an inlet pas sage 21 leading from a port or hose-coupling nipple 22 toward an inlet zone 23 confronting the axis at one end 24 of a fixed spindle 25 supporting a rotary impeller 35.

The spindle is fixed at one of its ends 25A on a wall portion 20A of the pump body in the aforesaid inlet zone, either as an integral part of the body casting or by means such as the screw 27 and recessed O-ring seal 28, and is thus in effect fixed at one end in a cantilever fashion to project into the pumping chamber with its free end 26 terminating still farther beyond in a well 60 which receives a hub portion and a driven coupling magnet, as will. more fully appear.

The pump body includes an impeller chamber 30 (FIG. 3 also) of annular shape having'an outlet passage 31 communicating into a discharge duct 32 and outlet port or hose nipple 33, the side of the pump body opposite the inlet zone being open and preferably of annular shape, also, for conjunction with a closure means.

An impeller 35 rotates on the spindle 25 and has a hub 36 on which is fitted an annular permanent magnet 37 cooperable with a larger external annular driving magnet 38 held in a rotating carrier 39 fixed on the shaft of a motor 40.

A liquid-impervious means for mounting the pum within the tank comprises a special housing or bell 50 having thecylindrical shape seen in FIGS. 4 and 5 with a large well '51 terminating in a flange 52 adapted to fit against the exterior of the tank at the margins 12A of a suitable opening formed in the sidewall of the tank, thishousing bell being clamped onto the tank against suitable sealing or gasket means such as an O-r'ing 53, by means of a clamp ring 54 secured by bolts 55, as in FIG. 2.

In the illustrative example described, the housing bell is formed of a molded plastic material, for example Polysulfone or the like, suitable to withstand the chemi cal action and wide temperature ranges obtaining in the tank, the inner wall portions of this structure including large post formations 57 having tapped bores to receive mounting bolts 58 by which the motorrnounting 'ring- 59. is secured, together with smaller posts 56 for the pump mounting bolts 64.

On the bottom wall of the bell is formed an inwardly and axially-aligned magnet well 60 which opens into an annular land 61, the diameter of which is slightly smaller than that of the open side of the pump housing so that the latter fits down about the margins of the land, the annular rim of the pump housing having a groove 20B molded therein to accommodate an O-ring 62 which seals the pump about the land when the pum mounting bolts 64are pulled in.

The magnet well has an internal diameter just sufficient to freely admit the hub portion 36 of the impeller and its driven magnet 37 to permit rotary clearance for the latter while minimizing the magnetic gap between it and the outer circumambient driving magnet 38.

Formed on the inner face of the bottom of the magnet well is a spindle-seating recess 65 which receives the free end 26 of the cantilever-supported spindle 25 in conjunction with the locating and securing interfit of the pump body rim about the land 61, and by this means the pump spindle is prevented from warping or skewing from the axial alignment needed for the rotational clearances of both the impeller and thedriven magnet. Such stabilization of the impeller spindle becomes of particular concern where the liquid circulated by the pump is at temperatures which will affect the rigidity and stability of the plastic material of the pump housing. In the illustrative application, the temperature of the bath ranges from about freezing to 190F. and it is difficult to keep the impeller spindle in sufficiently accurate alignment when the pump housing is formed of non-metallic plastic materials.

The stabilizing support for the free end of the spindle over which the impeller unit is to be fitted in assembling the pump may be utilized in forms of closure other than the motor mounting bell 50. For example, the closure may be in the form of the body member 70, shown in the modified construction of FIG. 5, comprising an annular plate portion 71 having marginal screw lugs 72 aligning with the screw posts 73 on the pump body section shown in FIG. 8. This closure plate is pro-. vided with an integrally-formedmagnet well 74 having the imperforate spindle-receiving recess or socket 75 molded on the inner side of its bottom wall.

The plate type closure 70 may be employed with the type of pump body 20 depicted in FIG. 3, in place of a mounting bell 50; or, it may be used with the modified. type of pump body 20Xv illustrated in FIGS. 6 and B, which is substantially like the body member 20 except that the footing or fixation of the spindle at one end is achieved by provision of a second spindle-seating socket situated in the inlet zone 23X to embrace the stud end 24X of the spindle as the primary support for the latter; and while the spindle may alternatively have its primary support in the magnet well, as disclosed in the aforementioned copending application Ser. No. 584,171, it is often preferable to keep the wall thicknesses of the magnet well minimal, and therefore to have the strength of the principal supporting seat or attachment for the spindle located in the inlet zone23X where the wall thickness need not be limited.

Means fixing the spindle 25X, FIG. 6, against rota tion along with the impeller may take the form of the keying configuration shown in FIGS. 7 and 8 wherein the stud end at the foot ofthe spindle 25X has a keying flat 81 formed therein to confront a companion flat 82 molded in the seating recess 80 formed at the inlet zone.

It will be apparent that as a result of the imperforate character of stabilizing support and socket structures such as 65, 75, 752, the impeller chamber is leak proof so far as the rotational support and driving of the impeller are concerned; and while the spindle has support at both of its ends, principally in the inletzone, and is thereby held in alignment, yet it may be fixed at one end against rotation, and also in attachment to the one of the two housing or body sections in which it is footed or fixed, so as to facilitate installation of the impeller and final assembly of the two housing or body sections. In the type of construction shown in FIG. 6 the fixed or principal mounting end 24X of the spindle can be force-fitted into its seat, in consequence of which, as in the case of the screw-secured spindle of FIG. 2, the spindles are held but optionally removable, so that a standardized body section may be equipped as necessary with spindles made from various materials or alloys for special requirements, as in the case of pumps for handling chemically active and corrosive liquids.

FIG. 9 illustrates a further modification of the construction of FIG. 6 wherein the spindle 252 is integrally formed as a part of one of the two pump housing sections, for example the body member 202, conformably with the disclosures of the aforesaid copending application Ser. No. 584,171; and the free end 262 of this integral spindle is secured against misalignment in a stabilizing socket 752 formed in the face of the inner bottom wall of the magnet well 74A. Such a construction has the advantage of permitting the use of a pump body and spindle molded in one piece from a choice of nonmetallic and synthetic plastic materials each suited to some particular working specification, such as might involve very hot or chemically reactive liquids having softening or corrosive effects on some but not other plastics.

It will be apparent that the Spindle mounting of FIG. 2 is such as to seize the spindle so that it will not rotate and will remain attached to the appertaining body member for easy assembly of the impeller structure thereon; yet this spindle is removable for replacement as required. In the construction of FIG. 6, the spindle is likewise secured against rotation, but may be optionally rendered loosely removable, or fixed, depending upon whether it is'seized in its footing or seating socket, as by force-fit or like means. The integral construction of FIG. 9 obviously renders the spindle permanently fixed in attachment to the appertaining body member. But in each of the foregoing embodiments the free or opposite and secondarily-supported end of the respective spindle is removably fitted into its supporting or aligning recesses as the result of assembly of the two body members.

It is also to be observed that in each of the aforesaid spindle-mounting arrangements the primarily fixed or foot end of the spindle is located in the corresponding inlet zone 23, 23X or 232 for the purposes and in accordance with the disclosures of the aforementioned copending application, which, briefly stated, provide for influx of the fluid at the principally stressed axial end of the impeller with such primary spindle support in the low-pressure zone of the entering fluid but at the end of the impeller axis at which the major stress will appear owing to the proximity of the displacing blades and the loading on the spindle which results at this end of the axis.

It will be further understood that, whereas the motor mounting bell 50 has been illustrated in dimensions of an adaptation which disposes the motor 40 only partially within the larger, outer well thereof, the depth of this well may be made great enough to receive and house the entire motor unit for those installations requiring an enclosed motor.

The detailed constructions disclosed and specifically described are illustrative of the character of the improvements and are not to be construed as limiting ex cept as the appended claims may particularly provide.

I claim:

1. A tank-mounting bell with combination driving motor and magnetically-coupled pump driven thereby, said bell comprising a molded plastics material shell of cylindrical form having one end closed by an integrally conformed end wall and an opposite open end; a plurality of post configurations disposed in angularly spaced relation in integral conformation with said material about the internal periphery of the shell cavity, certain of said post formations having end portions integrally terminating in said end wall, and others of said post formations having conterminous end portions disposed within the cavity away from said end wall toward said open end and constituting mounting lands; a motor mounting plate member seated against said lands and secured to the appertaining post formations; a pump driving motor having an end portion, at least, confronting and secured to said plate member with a predetermined substantial part, at least, of the motor body disposed within said cavity; a tank-mounting flange formation subtending said open end of the shell and constituting an integral configuration with the material thereof; a pump having a body engaged with the external sideof said end wall and secured thereto by means engaging into said certain post formations, said pump being adapted to be drivingly coupled with said motor by magnetic means which does not perforately penetrate said bell material.

2. The construction of claim 1 wherein said tankmounting flange formation extends radially outwardly of the shell and is adapted to seat against wall portions of a tank subjacent to the margins of a hole through which the bell is entered into the tank to a limit determined by engagement of said flange formation with said subjacent wall portions, and the bell is secured in sealed engagement with said subjacent wall portions by fastening means engaging both the flange and said lastmentioned tank wall portions.

' 3. A motor-mounting bell for use with a magnetically-coupled rotary pump of the type comprising a pump housing having a rotary impeller and coaxially rotatable driven magnet situated in a salient magnet chamber of the housing structure such that an annular outer driving magnet can be rotated about the outside periphery of the magnet chamber, improvements consisting in the combination with a pump housing of the aforesaid type having an opening through which the driven magnet of the impeller is a motor-mounting bell structure in the form of a one-piece cup-shaped member with a motor cavity open at one end for entry of a motor unit therein and having a bottom wall closing its opposite end and adapted to fit in sealing attachment to the pump housing in position to close off said opening thereof, said bottom wall having a chamber for the driven magnet which chamber is recessed inwardly of said cavity and impervious to fluid passage from the pump housing and into which the drive magnet projects; and means formed as an integral part of said bell member in the motor cavity thereof for supporting engagement with a motor unit received therein and including an annular driving magnet rotatable thereby with the axis of rotation of such magnet concentric with the axis of rotation of the driven magnet and the outer wall of said magnet chamber, whereby said annular driving magnet is disposed for rotation about the outer periphery of the outer wall of the magnet chamber as.

aforesaid, to impart driving torque to the driven magnet therein.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIQN Patent NO Dated Inventm-(s) Frederick N. Zimmermann It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 40,"FIG. 4;" should read "FIG. 5"; and column 6 line i2, after impeller is", insert "exposed of:

Signed and Scaled this A trest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer umml'ssium'r uj'lalenrs and Trademarks- 

1. A tank-mounting bell with combination driving motor and magnetically-coupled pump driven thereby, said bell comprising a molded plastics material shell of cylindrical form having one end closed by an integrally conformed end wall and an opposite open end; a plurality of post configurations disposed in angularly spaced relation in integral conformation with said material about the internal periphery of the shell cavity, certain of said post formations having end portions integrally terminating in said end wall, and others of said post formations having conterminous end portions disposed within the cavity away from said end wall toward said open end and constituting mounting lands; a motor mounting plate member seated against said lands and secured to the appertaining post formations; a pump driving motor having an end portion, at least, confronting and secured to said plate member with a predetermined substantial part, at least, of the motor body disposed within said cavity; a tank-mounting flange formation subtending said open end of the shell and constituting an integral configuration with the material thereof; a pump having a body engaged with the external side of said end wall and secured thereto by means engaging into said certain post formations, said pump being adapted to be drivingly coupled with said motor by magnetic means which does not perforately penetrate said bell material.
 2. The construction of claim 1 wherein said tank-mounting flange formation extends radially outwardly of the shell and is adapted to seat against wall portions of a tank subjacent to the margins of a hole through which the bell is entered into the tank to a limit determined by engagement of said flange formation with said subjacent wall portions, and thE bell is secured in sealed engagement with said subjacent wall portions by fastening means engaging both the flange and said last-mentioned tank wall portions.
 3. A motor-mounting bell for use with a magnetically-coupled rotary pump of the type comprising a pump housing having a rotary impeller and coaxially rotatable driven magnet situated in a salient magnet chamber of the housing structure such that an annular outer driving magnet can be rotated about the outside periphery of the magnet chamber, improvements consisting in the combination with a pump housing of the aforesaid type having an opening through which the driven magnet of the impeller is a motor-mounting bell structure in the form of a one-piece cup-shaped member with a motor cavity open at one end for entry of a motor unit therein and having a bottom wall closing its opposite end and adapted to fit in sealing attachment to the pump housing in position to close off said opening thereof, said bottom wall having a chamber for the driven magnet which chamber is recessed inwardly of said cavity and impervious to fluid passage from the pump housing and into which the drive magnet projects; and means formed as an integral part of said bell member in the motor cavity thereof for supporting engagement with a motor unit motor therein and including an annular driving magnet rotatable thereby with the axis of rotation of such magnet concentric with the axis of rotation of the driven magnet and the outer wall of said magnet chamber, whereby said annular driving magnet is disposed for rotation about the outer periphery of the outer wall of the magnet chamber as aforesaid, to impart driving torque to the driven magnet therein. 